INDUCES OF ANTIOXIDANT COMPOUNDS AND SALT TOLERANCE IN WHEAT PLANT, IRRIGATED WITH SEAWATER AS RESPONSE TO APPLICATION OF MICROALGAE SPRAY

Wheat plants (Triticum aestivum L., cv. Giza 168) irrigated with either 10 or 20% of Seawater (SW) were treated with aqueous extracts of green microalgae Scenedesmus obliquus and blue green algae Spirulina platensis (AESO and AESP 20 g (dry weight)/L) in order to increase wheat salt tolerance. Treated plants showed higher ability to tolerate salt stress (10 or 20% SW) by significant (p>0.5%) increasing of photosynthetic pigments (chlorophyll: Chlorophyll total, chlorophyll a and b types) and antioxidant low-molecular compounds (glutathione and carotenoids) contents. The increase of these contents was associated with increasing activities of antioxidant enzyme systems Superoxide Dismutase (SOD), Ascorbate Peroxidase (APX), Catalase (CAT) and total Peroxidase (POD). In addition, this observation was significantly correlated with decreasing of lipid peroxide products (TBARs) and sodium ions concentrations. However, wheat plant exposed to salt stress showed significant changes in all growth parameter and antioxidant low-molecular compounds and antioxidant enzyme activities compared with that in plants irrigated with regular water (tap water). In addition, plants treated with oxalic acid as bioregulator agent implied a moderate changes on growth parameters, antioxidant capacity includes non-enzyme and enzymatic systems compared with that in wheat plants treated with algae extracts. This study indicates that the algae extracts could be used as a promising plant growth enhancer for treating wheat plants irrigated with brackish water.